by wannabefree » Sat Oct 31, 2009 11:30 pm
You can spray varnish but there is no particular advantage to it. Varnish is painfully slow drying. It's formulated for brushing, not spraying. Put it on too thick and it will sag and alligator as it dries. You might do one coat in a day. You'll have trouble if you don't let it dry enough before the next coat.
If you spray, an HVLP gun is best. A modest conversion gun will cost $150, plus you need a pretty good compressor. A modest turbine gun runs $200+, but you don't need the compressor. The $20 HF guns just won't cut it. I mention all this because if you have no experience with a gun and don't plan on doing much other than the trailer you are better off finding someone else to do it for you. You can easily spend $400 on tools, more likely $600 to do a decent job. The pros don't sneeze at $500-1000 for a good gun.
All that said, there are definite advantages to spraying. You can use a faster finish, like clearcoat, and lay on 6-10 coats in a few hours. You can't say that for varnish. I recommend Emtek9300 from Target Coatings (they sell it on the web). It's not an automotive finish, but meant for wood and totally clear, not yellow like varnish. You can add dyes if you like. I put on 6 coats in about 3 hours. It's water-based, so cleanup is easy and the chemicals, while still noxious, are not as bad as with clearcoat. There is no smell and it won't turn into a rock in your gun like clearcoat will if you lose track of the time.
In anything at all, perfection is finally attained not when there is no longer anything to add, but when there is no longer anything to take away.
-- Antoine de Saint-Exupery